Heping Li

Hydrogen permeation barriers (HPBs) are essential to the development of both hydrogen and nuclear fusion energy. However, their structural stability and barrier efficiency under extreme conditions are scarcely reported, despite their significant importance to practical applications. Here, we experimentally investigated the effect of Li₄SiO₄ corrosion and deuterium aging on the structure and performance of an α-Al₂O₃ composite hydrogen permeation barrier coating under simulated fusion conditions. The results demonstrate that this coating could retain its dense and defect-free structure after corrosion with Li₄SiO₄ powders at 550 °C for 2 days, exhibiting good tritium breeder compatibility. Moreover, after the deuterium aging test for 6 months, its phase composition and microstructure show no significant changes, maintaining a compact and crack-free matrix strongly bonded to the substrate. After 6-month aging, the hydrogen permeation resistance of the α-Al₂O₃ composite coating at 500 °C is still 1450 times higher than that of the steel substrate without any aging. This work provides critical insights into designing highly reliable hydrogen permeation barrier coatings and understanding their performance evolution under harsh fusion environments.

Ceramic coatings have recently found applications as efficient hydrogen permeation barriers (HPBs) in the development of hydrogen and nuclear energy. Finding a simple method to increase hydrogen permeation resistance is essential for HPB applications. Herein, we fabricated an ultrathin zirconia (ZrO₂) coating using a facile sol-gel technique and increased its hydrogen permeation resistance via yttrium (Y) dopant tuning. With 12 mol % Y doping, the hydrogen permeation resistance of the 50 nm-thick ZrO₂ coating increased 10-fold, reaching 1019 times that of the austenite steel substrate. The mechanism behind this notable improvement was elucidated based on insights into the Y-dependent microstructural evolution of the ZrO₂ coating. Below 8 mol %, the Y dopant dissolved in the ZrO₂ lattice, reducing grain size. Greater Y content (>12 mol %) caused yttria nanoparticles to precipitate, generating a heterogeneous interface within the ZrO₂ coating and remarkably maximizing its hydrogen permeation resistance. Notably, this Y-doped ZrO₂ coating exhibited high thermal shock resistance, maintaining an intact structure after 80 thermal shock cycles under 600 °C water cooling. Heterogeneous interface design via doping may offer a distinctive approach to developing high-performance ceramic coatings for use as HPBs.

Ceramic coatings with high hydrogen permeation resistance are of great importance for protecting metal components from hydrogen attack. In this work, we fabricated an ultrathin (AlCrZr)O nanofilm with superior hydrogen barrier efficiency via a facile sol-gel technique. This novel ternary oxide nanofilm with an overall thickness of only 100 nm exhibits a high hydrogen permeation reduction factor (PRF) up to 2364 at 773 K, decreasing the hydrogen permeability by three orders of magnitude as compared to the steel substrate. The permeation cycling performance and thermal shock resistance of the nanofilm were further evaluated, which demonstrate good stability with its PRF consistently staying at a level of 10³. These excellent performances of the (AlCrZr)O nanofilm were attributed to its uniquely layered structure, consisting of an amorphous Al-Zr-O layer at the top and a crystalline Cr₂O₃ layer underneath. The amorphous layer without grain boundaries complicated hydrogen diffusion pathways and effectively increased hydrogen resistance. Meanwhile, the crystalline Cr₂O₃ layer could help to mitigate the thermal expansion mismatch between the nanofilm and the steel substrate, ensuring good stability of the barrier performance under thermal conditions. These findings underscore the significant potential of the (AlCrZr)O nanofilm for hydrogen embrittlement protection and provide a new framework for designing highly efficient hydrogen permeation barriers that combine superior performance with extended lifespans.

Hydrogen embrittlement in metals seriously threatens the safe and durable operation of hydrogen energy. Developing efficient and robust hydrogen barriers is a viable solution to solve this issue but remains a significant challenge. An amorphous (ErAlCrZrTi)O high‐entropy nanofilm is successfully fabricated via sol‐gel on steel and identified as highly efficient and robust hydrogen barrier. At 270 nm thickness, the nanofilm achieves ultra‐low hydrogen permeability of 1.35 × 10 ⁻¹⁵ mol m ⁻¹ s ⁻¹ Pa ^−0.5 , enhancing hydrogen resistance by 2738 times at 500 °C compared with that of bare steel. Compared to Er ₂ O ₃ , Al ₂ O ₃ , Cr ₂ O ₃ , and ZrO ₂ , it improves hydrogen resistance by 5, 11, 26, and 90 times, respectively. Moreover, such a high hydrogen resistance can be satisfyingly retained even after the (ErAlCrZrTi)O nanofilm suffering 10 dpa irradiation. The nanofilm exhibits 37 MPa bonding strength and exceptional thermal shock resistance, attributed to the formation of Cr₂O₃ transition layer via precipitation and oxidation of Cr from the substrate during annealing. It strengthens adhesion and alleviates thermal expansion mismatch with the substrate. The mechanism for the high barrier efficiency is further revealed by this theoretical calculations. These results provide tremendous insights on the understanding and future design of high‐performance hydrogen barriers for hydrogen embrittlement prevention.

Ceramic coatings that can effectively prevent hydrogen permeation have a wide range of applications in hydrogen energy and nuclear fusion reactors. In this study, for the first time, the internal stress of Er₂O₃ coatings was found to be a key factor that could determine their hydrogen permeation resistance and lifespan. The internal stress was controlled by designing layered Er₂O₃ coatings. The internal stress increased with an increasing number of Er₂O₃ layers. When the number of layers was below 15, the increased internal stress did not adversely affect the coating performance and might help to increase its hydrogen permeation resistance. Although the overall thickness of the 15-layer Er₂O₃ coating was only 97 nm, its hydrogen permeation reduction factor (PRF) reached the highest value of 626, whereas a further increase in the internal stress detrimentally affected the ability of the coating to reduce hydrogen permeation. In addition, the experimental observations and simulation results revealed that the performance of the Er₂O₃ coatings was related to the hydrogen atoms that penetrated the coating, which weakened the Er-O bonds and consequently decreased the Er₂O₃ fracture limit. This study provides insights into the effects of internal stress and hydrogen penetration on the performance of ceramic coatings as hydrogen permeation barriers and will help guide strategies for the structure design of hydrogen permeation barriers possessing high PRFs and long lifespans.

In this study, a Cr₂O₃ nanosheet (Cr₂O₃ NS) inserted Cr-Zr-O coating was developed as a hydrogen isotope permeation barrier. The Cr₂O₃ NSs, fabricated by rapid heat treatment, were amorphous with a thickness of only several nanometers. These Cr₂O₃ NSs were then incorporated into a Cr-Zr-O multi-metal oxide composite coating via a dip-coating method to form a coating. The effect of the Cr₂O₃ NS concentration on the morphology, microstructure and deuterium permeation resistance of the coating was studied. With the addition of 1.0 g l⁻¹ Cr₂O₃ NSs, compared with the Cr-Zr-O coating without NSs, the permeation reduction factor of the resultant coating was enhanced from 249 °C to 575 °C at 500 °C. The coating, with a thickness of nearly 193 nm, achieved a comparable deuterium resistance that was above two orders of magnitude higher than the steel substrate. The results show that ceramic NSs can serve as effective fillers for enhancing the coating performance when functioning as a hydrogen isotope barrier.

Hydrogen isotope permeation through structural materials is a key issue for developing nuclear fusion energy, which will cause fuel loss and radioactive pollution. Developing ceramic coatings with high thermal shock and hydrogen resistance is an effective strategy to solve this issue. In this work, a layer-structured Cr/Cr_xN coating was successfully fabricated by a facile electroplating-based nitridation technique, which is easy, facile, and applicable to coating complex-shaped substrates. The Cr/Cr_xN coating, composed of a bottom Fe/Cr interdiffusion zone, a middle Cr layer, and a top Cr_xN layer, exhibits high bonding strength, high anti-thermal-shock ability, and high deuterium permeation resistance. Its bonding strength achieves 43.6 MPa. The Cr/Cr_xN coating remains intact even after suffering 300 thermal shock cycles under a 600 °C-water condition. Through optimizing the nitridation temperature, the Cr/Cr_xN coating achieves a deuterium permeation reduction factor (PRF) as high as 3599 at 500 °C. Considering its scalable fabrication technique and considerable properties, the developed Cr/Cr_xN coating may serve as a novel high-performance hydrogen permeation barrier in various fields.

Purpose: This study investigated the factors that influence the prognosis of swallowing function rehabilitation therapy in patients with dysphagia after medullary infarction. Patients and Methods: This retrospective study was conducted using the clinical data of 51 patients who were diagnosed with dysphagia after medullary infarction and hospitalized at our institution between January 2019 and January 2021. As per the water swallow test (WST) grade at 1 month after rehabilitation treatment, patients were classified into the good prognosis group and the poor prognosis group. Univariate analysis as well as univariate and multivariate logistic regression analysis were used to analyze factors that influence the prognosis of swallowing function rehabilitation therapy in patients with dysphagia after medullary infarction. Receiver operating characteristic (ROC) curves were then used to test the predictive ability of the significant parameters to predict the prognosis of the rehabilitation therapy in these patients. Results: Univariate analysis and univariate logistic regression analysis showed that previous stroke (odds ratio [OR] = 1.361), dysarthria (OR = 3.771), disease course (OR = 1.112), National Institutes of Health Stroke Scale (NIHSS) score at admission (OR = 2.596), and infarct site (OR = 11.071) were all significantly correlated with the prognosis of swallowing function rehabilitation therapy in patients with dysphagia after medullary infarction (P < 0.05). Multivariate logistic regression analysis showed that dysarthria (OR = 5.519, 95% confidence interval (CI) 1.413– 21.566), infarct site (OR = 18.634, 95% CI 1.696– 204.73), and the NIHSS score (OR = 1.001, 95% CI 1.536– 4.820) were independent influencing factors of the prognosis of swallowing function rehabilitation therapy in these patients. The ROC curve showed that the area under the curve for the combined prediction of the three indicators was 0.943. Conclusion: The NIHSS score, dysarthria, and infarct site are independent influencing factors for the prognosis of swallowing function rehabilitation therapy in patients with dysphagia after medullary infarction.

Ceramic fiber photocatalysts fabricated by electrospinning hold great potential in alleviating global environmental and energy issues. However, many challenges remain in improving their photocatalytic efficiencies, such as the limited carrier lifetime and solar energy utilization. To overcome these predicaments, various smart strategies have been invented and realized in ceramic fiber photocatalysts. This review firstly attempts to summarize the fundamental principles and bottlenecks of photocatalytic processes. Subsequently, the approaches of doping, surface plasmon resonance, and up-conversion fluorescent to enlarge the light absorption range realized by precursor composition design, electrospinning parameter control, and proper post heat-treatment process are systematically introduced. Furthermore, methods and achievements of prolonging the lifetime of photogenerated carriers in electrospun ceramic fiber photocatalysts by means of introducing heterostructure and defective composition are reviewed in this article. This review ends with a summary and some perspectives on the future directions of ceramic fiber photocatalysts.